Both Genes, Environment Contribute to Metabolic Syndrome-CKD Link

In a study of Swedish twins, investigators worked out the relative effects of genes and the environment on the correlation between metabolic syndrome and chronic kidney disease.

Both genes and environment are
responsible for the link between metabolic syndrome and chronic kidney disease (CKD),
according to new research published in the Clinical
Journal of the American Society of Nephrology.

In a study of 4721 sets
of Swedish twins born between
1911 and 1958 (44% male), 34% had metabolic syndrome and 20% CKD stage 3 or
higher. Metabolic syndrome and CKD phenotypically correlated by a coefficient
of 0.16, according to Xu Chen, MD, of the Institute for Maternal Fetal Medicine
in China, and collaborators. Fifty-one percent of the correlation was explained
by genes, 34% by nonshared (unique) environment, and 15% by common environment.
Genetic and environmental correlations were also positive at 0.29 and 0.27,
respectively.

Genetics particularly
contributed to the correlation between abdominal obesity (ie, waist circumference
exceeding 40 inches for men and 35 inches for women) and estimated glomerular
filtration rate (eGFR) determined by cystatin C. This finding suggests “a
central role for abdominal obesity in the link between metabolic syndrome and
CKD.”

“Our results indicate that
the observed genetic contribution to the correlation between metabolic syndrome
and eGFR-defined CKD in our study is compatible with a direct effect of metabolic
syndrome on CKD,” Dr Chen’s team concluded.